The research was conducted by political scientists at Trinity College Dublin (TCD) and the University of Exeter in the UK and analysed more than 16,000 publications about climate change by 19 major conservative thinktanks in the US over 15 years from 1998 to 2013.
Thought to be the largest study of such material, the research was published in the Journal of Global Environmental Change. It found, despite the vast majority of scientists having reached a consensus on global warming, arguments against the science of climate change are on the increase.
The study involved an examination of 8,300 articles, 3,000 reports, 100 interview transcripts, 680 press releases and open letters, and 3,900 scientific reviews over 15 years.
Overall, it found “the era of climate science denial is not over” and conservative thinktanks have not shifted from questioning the science of climate change to focusing on policy debates.
“On the contrary, the study revealed challenges to climate change have been on the rise in recent years.”
The research also found the overall level of material being produced by conservative thinktanks on climate change has grown rapidly over the past decade-and-a-half reaching a peak during late 2009 and early 2010.
Debate around scientific integrity began to overtake that of energy policy during 2006 and 2007, corresponding to the release of former US vice-president Al Gore’s film An Inconvenient Truth and his acceptance of the Nobel Peace Prize.
Assistant professor in political science at TCD, Constantine Boussalis, said the rise in scepticism was a disturbing trend. “While the level of uncertainty surrounding the causes and consequences of climate change has decreased, the emphasis on climate science scepticism by conservative think- tanks has increased over time. This is a disturbing trend, as a general acceptance of human-caused global warming is a necessary condition for a comprehensive agreement on climate change mitigation,” he said.
Lecturer in quantitative political science at Exeter University Travis Coan said conservative thinktanks have played a role in generating the narrative of climate change scepticism and, by extension, obstructing climate policy in the US.
“The vast majority of climate scientists agree that the Earth is warming and that observed changes in the global climate are predominantly attributable to human activity,” he said. “Nevertheless, a significant segment of the American public and many lawmakers in the US Congress continue to deny this reality.”